(a) Field of the Invention
The present invention relates to a brake control system and method, in particular, to a brake control system and method for preventing a vehicle from rolling downward when starting on a slope and for providing driving stability by automatically controlling brake force when parking and stopping.
(b) Description of the Related Art
A brake system is an important safety system used to bring a vehicle to a safe controlled stop and maintain the vehicle in a stationary state. Accordingly, the brake system requires durable braking ability considering the top speed and weight of the vehicle and the brake system itself must not obstruct the rotation of wheels when it is not operating.
Brake systems are classified into mechanical brakes, hydraulic brakes, servo brakes, and air brakes according to their operating method. Among them, the air brake systems are widely used for heavy-duty vehicles such as trucks and trailers because the air brakes can obtain high brake forces using relatively low control pressure.
However, the air brake systems cannot still satisfactorily operate for the heavy-duty vehicle especially when the vehicle restarts after stopping on a slope. That is, the heavy-duty vehicle may roll downward due to the weight of the vehicle and its load when starting on the slope. To avoid the vehicle's rolling downward on the slope, drivers should push the acceleration pedal to increase engine torque. This kind of operation leads to an incomplete combustion of fuel, a decreased air/fuel ratio, and noise creation.
Therefore, a slope start auxiliary device preventing a vehicle from rolling downward on a slope has been used. Japanese Laid-Open Patent No. 95-48017 discloses a slope start auxiliary device using a 5-way control valve for maintaining front and rear wheels in a locked state. However, the 5-way control valve makes the operation of device very complex. In addition, if the control valve breaks down, brake service is not available and it is impossible to use the slope start auxiliary device.